In September this year, the highly anticipated 19th Asian Games will be held in Hangzhou. Several months ago, with the successful breakthrough of the "Qinlong No. 1" large-diameter shield machine, the entire Huancheng North Road-Tianmushan Road upgrading and renovation project in Hangzhou was successfully completed.

Tianmushan Road is the main traffic artery for entering Hangzhou from the west and one of the important support roads for the Hangzhou Asian Games. To ensure high-quality and safe shield tunnel construction, the contractor specially purchased two 13.46-meter large-diameter slurry balance shield machines independently developed and produced by China Railway, named "Qinlong No. 1" and "Qinlong No. 2" respectively.

A single shield machine has a total length of about 133 meters, a total weight of about 3,200 tons, and an excavation diameter of 13.46 meters. The cutterhead adopts a rock-breaking design and is fully covered and protected by wear-resistant composite steel plates, enabling it to handle excavation in rock formations with a strength of 100 MPa with ease. Equipped with intelligent systems such as intelligent remote safety monitoring and management and automatic guidance, shield construction is more scientific and efficient.

During construction, the two shield machines mainly passed through tuff, clay, gravel-bearing siltstone and other strata, crossing 11 fracture zones, urban surface rivers, underground pipelines and densely built-up areas. The complex geology placed high demands on settlement control and geological adaptability during equipment construction, but all technical indicators of the project reached the international leading level.

During the construction process, the project yielded fruitful results in scientific research and innovation. It established two major scientific research projects at the China Railway level and one each in Zhejiang Province and Hangzhou City, successfully applied for 13 patents, and published 6 core papers including "Adaptability Design of Large-Diameter Slurry Shields in Strata with Variable Upper-Soft and Lower-Hard Rock Properties."